The present invention is in the field of optical instruments and more particularly, optical microscopes.
Optical microscopes have long been adapted for viewing objects on planar surfaces of glass slides. Such microscopes generally include an optical system which provides an image of an object in an associated focal plane. A stage, or carrier, assembly holds the object-bearing slide surface substantially parallel to the focal plane of the optics.
Generally, the stage is movable in two perpendicular directions in a plane parallel to the focal plane in order to permit selective movement of a slide mounted on the stage past the field of view of the optics system. In the prior art, these movements are accomplished by mechanical linkages, which, for example, may include ways or bearings. In order to provide relatively high-accuracy control of the movements of the stage, the linkages require precision and correspondingly expensive components. Typically, preloaded mechanical stages may have as much as 50 microns of defocusing motion over a 1-inch by 2-inch slide area. As a result, relatively large ranges of motion are required along the optical axis to provide satisfactory focusing over the range of slide motion. It is known in the prior art to use a vacuum chuck coupled to the stage for supporting a slide against a slide registration surface substantially parallel to the focal plane in an optical microscope, for example, as taught in U.S. Pat. No. 3,848,962. This type of slide mounting apparatus permits satisfactory support for a slide, maintaining the object-bearing surface in a plane parallel to the focal plane for slides having varying wedge or thickness and coverslip thickness.
However, in many applications it is also necessary that an object-bearing slide have a desired alignment which may be repetitively achieved. This is particularly necessary for automated microscopy systems in which a particular location on a slide may be re-accessed a number of times.
It is an object to provide a microscope system which is relatively easy to fabricate at correspondingly low cost.
It is another object of the present invention to provide a microscope system having improved positioning control for object-bearing slides.
It is yet another object to provide a microscope system having an improved method for selectively aligning and supporting a microscope slide.